CVE-2026-45838

Data disclosure via wrapped list iteration

Published May 27, 2026 · Updated May 27, 2026

Out-of-bounds read in Linux Kernel BPF cgroup storage allows local users to expose kernel map data through a storage-key query. In cgroup_storage_get_next_key(), list_next_entry() wraps the last element to the list head, so a dead NULL check permits storage->key to be read through a bogus pointer and copied to userspace. Exploitation requires CAP_BPF in the initial user namespace and exposes aliased internal map data; Ubuntu grants that capability only to uid 0.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Linux Kernel BPF cgroup storage allows local users to expose kernel map data through a storage-key query. In cgroup_storage_get_next_key(), list_next_entry() wraps the last element to the list head, so a dead NULL check permits storage->key to be read through a bogus pointer and copied to userspace. Exploitation requires CAP_BPF in the initial user namespace and exposes aliased internal map data; Ubuntu grants that capability only to uid 0.

The record

CVE
CVE-2026-45838
Published
May 27, 2026
Updated
May 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1005
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.19
  2. Affected versionversion=de9cbbaadba5adf88a19e46df61f7054000838f6 <32ce55d424395904986f5066f8755f6cb9993377
  3. Affected versionversion=de9cbbaadba5adf88a19e46df61f7054000838f6 <5828b9e5b272ecff7cf5d345128d3de7324117f7
  4. Affected versionversion=de9cbbaadba5adf88a19e46df61f7054000838f6 <85a2f30e40f7468db732f55659bc6318874f49af
  5. Affected versionversion=de9cbbaadba5adf88a19e46df61f7054000838f6 <b4b5a20bed82130da2f2818f04d52378952fbd0b
  6. Affected versionversion=de9cbbaadba5adf88a19e46df61f7054000838f6 <fc39753b7f92e09177777e9c648afe5aa3abb81f

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.19; version=de9cbbaadba5adf88a19e46df61f7054000838f6 <32ce55d424395904986f5066f8755f6cb9993377; version=de9cbbaadba5adf88a19e46df61f7054000838f6 <5828b9e5b272ecff7cf5d345128d3de7324117f7; version=de9cbbaadba5adf88a19e46df61f7054000838f6 <85a2f30e40f7468db732f55659bc6318874f49af; version=de9cbbaadba5adf88a19e46df61f7054000838f6 <b4b5a20bed82130da2f2818f04d52378952fbd0b; version=de9cbbaadba5adf88a19e46df61f7054000838f6 <fc39753b7f92e09177777e9c648afe5aa3abb81f

Published CVSS scores

3.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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